Certain typical vehicle lighting devices, such as low beam headlamps and fog lamps, provide forward illumination when driving. These lamps are required to be properly aimed to avoid glare light for on-coming vehicle drivers. A traditional approach to design a projector type headlamp or fog lamp is to use a light shield fixed inside the lighting device. The light shield blocks a portion of the light emitted from the lamp to prevent glare so that the light beam can meet certain performance or regulatory requirements.
Unfortunately, however, headlamps are typically affixed to the vehicle and the direction of the light beam is determined by the facing of the vehicle body. Therefore, when certain vehicles, e.g., motorcycles, are driving on a curved road or making turns, the light beam tilts with the vehicle and, thus is not properly aimed for direct forward illumination. Because the light shield is usually fixed in relation to the lamp, the light shield will direct the light beam in the direction in which the vehicle is facing, not in the direction of the curved road.
Some light devices vertically adjust light beam distribution by rotating the light shield using a mechanical or an electrical device, such as by way of an electric motor. This requires use of a complicated supporting structure, and also limits the adjustment of the light beam in the vertical direction, which fails to provide a desired light distribution when a vehicle makes a turn. Moreover, some other known devices provide a horizontal aiming feature (U.S. Pat. No. 3,939,339), with an aiming device mounted outside of the light module. Therefore, in these types of know devices, the entire light module or lamp assembly must be moved to achieve the aiming location.